It has long been known that the night visibility of pedestrians and other persons in the area of automobile traffic is greatly improved to motorists by the wearing of light-reflective clothing. It is known that the visibility of garments and wearing apparel at night can be enhanced by sewing reflective bands or strips into the garments, and by incorporating light-reflective particles into fabrics from which the garments are made.
Light-reflective properties of various substrate materials, such as fabrics, have heretofore been enhanced by coating or laminating the materials with a layer of reflex-reflective glass microspheres, or beads. Such microspheres are commercially available and generally comprise small spherical glass beads which are hemispherically coated with a thin film of light-reflective metal, such as aluminum, and an overlying resinous binder of thermoplastic material. Typically, such reflex-reflective glass bead coatings are produced by uniformly applying glass microspheres to an adhesively coated carrier sheet, and then coating their exposed hemispheric surfaces with the reflective metal and the thermoplastic binder.
It has been a practice to then laminate the binder-coated face of such reflex-reflective sheet to a fabric substrate, with application of heat to activate the binder and bond it to the fabric surface. The carrier sheet is then stripped from the glass bead layer to produce a resultant fabric product having a mono-layer of reflex-reflective beads on the fabric surface, with the beads uniformly oriented to expose their hemispherically reflective surfaces away from the fabric surface for optimum light reflectance. U.S. Pat. Nos. 3,164,645; 3,172,942; and 3,758,192 are illustrative of such a manner of producing reflex-reflective glass bead sheets, and the methods of laminating such glass bead sheets to fabric substrates.
Although such coated fabrics exhibit improved light reflectivity, there are certain disadvantages for their manufacture and use in garments and wearing apparel. Since conventional textile fabric finishing operations generally do not utilize laminating equipment, the expense of acquiring and operating such equipment adds to the cost of manufacture of the fabrics. More importantly, it is believed that a laminated coating layer of glass beads on the fabric surface decreases fabric drapability and flexibility and resultant wear comfort of garments made therefrom. Such coatings of glass beads also appreciably alters and detracts from the normal daytime visual appearance of the garments and causes an off-color or dingy appearance of the fabrics, making garments produced therefrom often aesthetically unattractive for normal daytime wear.
More recently, it has been proposed to incorporate reflex-reflective glass beads into textile fabrics by a dry particle method of application wherein reflex-reflective beads having a magnetizable component in their hemispheric coating are applied in discrete particle form to the surface of the fabric, and thereafter the fabric is subjected to a magnetic force field to orient the light-reflective surfaces of the beads outwardly of the fabric before activation of the binder resin. Attempts to utilize such a dry method application of the magnetizable glass beads in commercial textile fabric manufacturing operations have not proved satisfactory for several reasons.
First, conventional textile fabric manufacturing and finishing operations do not have available the necessary equipment for dry application of reflective bead incorporation into the fabrics; therefore, the purchase and installation of additional equipment not commonly used or readily available in textile dyeing and finishing plants adds appreciably to the cost of manufacturing. Second, attempts to employ a dry method of application of the reflective beads has shown that, for textile fabrics, uniform metering and application of the particles on the fabric is difficult in a continuous production line operation, and the particles often become located within the interstices of the fabric before they can be properly oriented and fixed by activation of the thermoplastic binder to the fabric. Thus, a large portion of the effective light reflectance of the beads may be lost due to improper location and orientation of the beads adjacent the fabric surface. In addition, attempts to fix the glass particles via their thermoplastic binder in a dry application have not yielded satisfactory levels of durability of the particles on the fabric under laundering conditions to which garments made therefrom are subjected.
Thus, although reflex-reflective particles are readily available for improving light reflectivity of various articles and substrates, I know of no satisfactory economical method of applying the particles in a commercial textile finishing operation.
U.S. Pat. No. 3,535,019 discloses a liquid composition having reflex-reflective elements, i.e., glass microspheres which are hemispherically metallized to have a specular-reflecting, hemispherical surface, which composition is suggested be applied to a fabric in a desired pattern by screen printing or spraying. However, it is believed that such paintlike coatings applied to fabrics generally stiffen the fabrics in the area of application, and interfere with the drape and comfort of garments made from the fabrics during wear. Problems also exist when applying such reflex-reflective glass spheres to fabrics to orient the spheres so that their light-reflective surfaces face outwardly of the surface of the fabric to provide optimum light-reflectivity with minimum application of the glass particles.